Three methods for local repair of flanges

The application of flange plays an important role in many aspects, including petrochemical industry, energy industry, scientific research and military industry. However, in the reactor of refinery, the production environment of flange is very bad, and the performance of flange must be excellent, because there are flange interfaces such as inlet and discharge port with pressure and temperature sensor in the reactor. Defects such as damage, scratch and crack of flange sealing surface are easy to appear during the use of the container, which affects the sealing performance of flange. Here are some preventive measures that should be taken against this situation.

Nicked alloy cladding flanges 825 alloy material weld overlay on the base material ASTM A335 P11

There are three main methods to deal with it:

First, increasing the tightening torque value of flange bolts is suitable for flange sealing surfaces with slight corrosion and scratches.

Secondly, the grinding ring is used for manual on-site grinding repair for local surfacing welding of sealing surface in small area.

Thirdly, this method is usually adopted when the sealing surface with serious cracks or defects must be repaired off-line and can not be repaired or meet the requirements on-line. That is to say, the container is disassembled and transported to the manufacturer, and then cracks are removed, repaired and heat treated, and then processed by a large-scale numerical control device. Large cranes and transportation equipment are needed for the disassembly and transportation of containers, which is expensive and has a long construction period, causing great economic losses to petrochemical enterprises.

In addition, due to the inconveniences and disadvantages in the processing and repairing of container flanges on site, it is very necessary to design a process for repairing and reprocessing flanges directly on site, to ensure the real-time repair and perfection of flange.